Metamath Proof Explorer


Theorem refrelsredund3

Description: The naive version of the class of reflexive relations { r e. Rels | A. x e. dom r x r x } is redundant with respect to the class of reflexive relations (see dfrefrels3 ) in the class of equivalence relations. (Contributed by Peter Mazsa, 26-Oct-2022)

Ref Expression
Assertion refrelsredund3
|- { r e. Rels | A. x e. dom r x r x } Redund <. RefRels , EqvRels >.

Proof

Step Hyp Ref Expression
1 refrelsredund2
 |-  { r e. Rels | ( _I |` dom r ) C_ r } Redund <. RefRels , EqvRels >.
2 idrefALT
 |-  ( ( _I |` dom r ) C_ r <-> A. x e. dom r x r x )
3 2 rabbii
 |-  { r e. Rels | ( _I |` dom r ) C_ r } = { r e. Rels | A. x e. dom r x r x }
4 3 redundeq1
 |-  ( { r e. Rels | ( _I |` dom r ) C_ r } Redund <. RefRels , EqvRels >. <-> { r e. Rels | A. x e. dom r x r x } Redund <. RefRels , EqvRels >. )
5 1 4 mpbi
 |-  { r e. Rels | A. x e. dom r x r x } Redund <. RefRels , EqvRels >.